feat: convert to argument.es — Spanish, vote buttons, Docker

- Translate all ~430 prompts to Spanish with cultural adaptations
- Translate all UI strings (frontend, admin, history, broadcast)
- Translate AI system prompts; models now respond in Spanish
- Replace Twitch/Fossabot viewer voting with in-site vote buttons
- Add POST /api/vote endpoint (IP-based, supports vote switching)
- Vote buttons appear during voting phase with active state highlight
- Rename project to argument.es throughout (package.json, cookie, DB)
- Add docker-compose.yml with SQLite volume mount
- Add .env.sample documenting all required and optional vars

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

db.ts

@@ -1,7 +1,7 @@
 import { Database } from "bun:sqlite";
 import type { RoundState } from "./game.ts";
 
-const dbPath = process.env.DATABASE_PATH ?? "quipslop.sqlite";
+const dbPath = process.env.DATABASE_PATH ?? "argumentes.sqlite";
 export const db = new Database(dbPath, { create: true });
 
 db.exec(`